Sheet metal layout instrument



y 4, 1953 w. ALTNETHER 2,645,028

SHEET METAL LAYOUT INSTRUMENT Filed April 11, 1952 A. 4 22 A? 2/3 23 a 4 i 22 I Z INVENTOR.

WILLIAM A 'r/v: THE)? 8/ W #1 fl-rro RA/l/ Patented July 14, 1953 OFFICE} SHEET METAL LAYOUT INSTRUMENT William Altnether, St. Louis, Mo.

Application April 11, 1952, Serial No. 281,768

1 Claim.

The present invention relates generally to a device for use in sheet metal layout work.

More particularly, the invention relates to a novel device adapted to mechanically solve some of the workshop problems which arise in sheet metal drafting when parallel line development of patterns is requisite.

Specifically, the invention provides an instrument which obviates the time-consuming procedure heretofore employed in parallel line develop ment of patterns for cylinders and elbows.

Prior to the present invention, the layout of cylinders and elbows, as taught in sheet metal workers manuals and in accordance with ac,- cepted practice, involved numerous steps, includ ing the time-consuming step of dividing a semicircle into a number of equal parts by means of a divider.

The latter operation, although not too tedious when the desired diameter was relatively small, has heretofore presented a considerable problem when relatively large diametered layout work was involved, as is understood.

The primary object of the present invention is to provide a device which is designed to dispense with the use of the compass and a pair of dividers in layout work of this character.

To this end, the invention incorporates means for automatically providing the proper spacing for any given diametered cylinder or elbow pattern within its range, as will appear.

Further objects and advantages will be apparent or pointed out in the detailed description of the invention to follow reference being had also to the accompanying drawing.

In said drawing:

Figure l is a plan view of an instrument embodying the present invention, the device being shown in normal status;

Figure 2 is an edge view thereof;

Figure 3 is a view similar to Figure 1, the device being shown in a status of extreme adjustment;

Figure 4 is an enlarged fragmentary vertical sectional View taken on the line 44 of Figure 1;

Figure 5 is a similar view taken on line 55 of Figure 1;

Figure 6 is a fragmentary view similar to Figure 4 illustrating a slightly modified pivotal connection; and

Figure 7 is a schematic layout for reference in demonstrating how the objectives of the invention may be attained.

Referring particularly to Figures 1 through 3, the instrument comprising the instant invention is designated generally by the numeral l0.

of similar bars M which, for purposes of this description, will hereinafter be termed the lower end bars. The two pairs of end bars l2 and M are parallel and are counterparts, as shown.

A plurality of what will hereinafter be termed divider bars, connect and are each pivotally secured at their opposite extremities to the pairs of end bars. Included are a left-hand divider bar 56, a right-hand divider bar l8, and a number of similar intermediate bars 20. All of the divider bars are parallel and are counterparts, as shown.

As also appears in the drawing, the upper extremity of each divider bar lies between, and has a pivotal connection 22 with the upper end bars l2. Similarly, the lower extremity of eachdivider bar lies between, and has a pivotal connection 24 with the lower end bars [4.

As particularly portrayed in Figure 4, the pivotal connections 22 and 24 are inthe form of rivets, whereby friction obtaining between the end bars and the divider bars serves to maintain the instrument ID in a selected position of adjustment. If desired, a more positive arrangement, such as that illustrated in Figure 6, may be incorporated at one or at opposite corners, as should be manifest.

In Figure 1 the device In is presented in its normal status, and this view has been selected for the immediately following description.

Thus, beginning at the left-hand divider bar 16 and progressing to the right-hand bar IE, it should be apparent that the spaces obtaining between adjacent divider bars are of successively decreasing extent. The specific spacing of the divider bars is based on well known sheet metal drafting principles, the distances between successive bars being directly proportional to the projections of equal divisions of a quadrant on a diameter thereof passing through the end of the quadrant.

A first diagonal row of small holes provided in the divider bars, are each of a size to receive a stylus or similar pointed marking instrument. Said first row includes the hole 26 in left-hand bar [6, holes 28, 33, 32, 34, and 36 in the intermediate bars 20, and the hole 38 in right-hand bar l8.

A second diagonal row of similar holes, which intersects the first row at the hole 30, is provided in the divider bars; That is to say, this second row includes the hole 40 in the left-hand bar IS, the hole 42 in the adjacent intermediate bar 20, said hole 30 in the next intermediate bar,

3 holes 44, 46, and 4B in the remaining intermediate bars, and the hole 50 in the right-hand bar 18.

Prior to entering into an explanation of the manner in which the instrument 10 may be em-- ployed to attain the objectives of my invention, it should be observed that the diagonal disposition of the intersecting rows of holes is a noteworthy feature.

In other words, with said arrangement, an instrument constructed in accordance with the teachings of this invention exhibits the paramount diiferential obtainable within'the limits thereof, as a comparison of Figures 1 and 3, augmented by the explanation to follow with reference to Figure '7 should demonstrate.

It is here observed however, that although obviously the instrument may attain all of its objectives with only one row of holes, the two ows have been provided to facilitate the use of the instrument in actual practice. In other words, since the primary objective of the invention is directed to a time-saving'instrument, the provision of two rows of holes is preferable, because the relative disposition of the holes resulting from the previous layout is at once apparent, so that a minimum of manipulation is required to adjust the instrument for the next layout.

Assuming that a pattern for an elbow having a diameter of twelve inches is required, a line exactly twelve inches long is drawn on a sheet of detail paper, and a point is marked at the center thereof. In Figure '7, the line referred to extends from point a to point b with center point obviously six inches from either a or b.

The device in its normal or Figure 1 status, is now positioned with hole 40 in registry with point e, whereupon manual downward and rightward pressure is applied to the upper end bars I2 until the hole 50' is in registry with point b.

Assuming that the illustrated device has been designed for diameters between for example, nine and eighteen inches, the manipulation just described adjusts the device to a position intermediate the normal portrayed in Figure 1, and the fully extended or extreme position portrayed in Figure 3.

In other words, with the assumed range above stated, the distance between holes 40 and 50 with device lflin its Figure 3 position, would be approximately eighteen inches, whereas the distance between holes 2 6 and 38 would be approximately nine inches.

Reverting to Figure '7, with hole 4'0 in registry with point e and hole 50 with point b, a stylus or other pointed instrument such as a pencil, may be employed to successively mark point at via hole 42, point e via hole 30, point 1 Attention is directed however, to the fact that the identical spacing obtainable by means of the device along the line a-b, may be obtained in similar fashion by applying the device to the miter line mZ if desired, and regardless of what the degree of miter line angularity may be.

It should be apparent without further elaboration, that spacing for a small diametered cylinder or elbow is accomplished in the same manner, except that the diagonal row of holes 26, 28, 30, 32, 34, 36, and 38 would be utilized for the markings.

From the foregoing description, augmented by the drawing, it should be apparent that this invention discloses an instrument which is simple in design, which does not require any particular skill for the successful use thereof, and which is adapted to eliminate the most tedious step of sheet metal layout work with reference to producing cylinder and elbow patterns.

It is of course to be understood that the embodiment illustrated and described may be structurally modified in some respects without departing from the spirit and principles of the invention. Therefore, the scope of the invention is to be limited only as defined by the appended claim.

What I claim is:

An instrument for automatically determining the proper spacing of points to be marked on a line representing the diameter of a circle for laying out an elbow in sheet metal drafting, including in combination: and upper and a lower end bar in spaced parallel relation; a left end divider bar, a right end divider bar, and a plurality of intermediate divider bars, each of said bars having a pivotal connection at one end with said upper and at the opposite end with said lower end bar, and all of said divider bars being parallel and so disposed that the distances obtaining between adjacent ones are of successively decreasing extent from the left to the right end divider bar, the distances between adjacent bars being directly proportional to the projections of equal divisions of a quadrant on a diameter thereof; and at least one diagonal row of holes provided in said divider bars for marking points with a stylus and the like along the line aforesaid, one hole of said row being formed in each divider bar with the distances between adjacent pairs of holes from the left to the right end divider bar being of successively decreasing extent in accordance with sheet metal drafting 1 principles.

via hole 44, point g via hole 46, and point h via I WILLIAM ALTNETHER.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 344,014 Stevenson June 22, 1886 663,053 Wangler Dec. 4, 1900 2,327,058 OKeefe Aug. '17, 1943 2,561,020 Gerber July 1'7,

FOREIGN PATENTS Number Country Date 83,915 Austria May 10, 1921 382,738 Germany Oct. 5, 1923 

